Late Mesozoic felsic magmatism and Mo-Au-Pb-Zn mineralization in the southern margin of the North China Craton: A review

Abstract

The widespread large-scale Mo-Au-Pb-Zn mineralization in the southern margin of the North China Craton (NCC) is spatially and temporally associated with the voluminous late Mesozoic granitic magmatism. Relationship between the granitic magmatism and ore mineralization has been extensively investigated in the last decade. However, controversy still exists regarding the magma source, metallogeny and geodynamic settings. This paper systematically reviews the major features of the Mesozoic granitic magmatism and associated Mo-Au-Pb-Zn mineralization in the southern margin of the North China Craton, including temporal and spatial variations of magmatic rocks, composition of ore-fluids, sources of ore metals, and metallogeny. The granitic rocks were mainly formed in late Mesozoic and emplaced in two stages. The early-stage (158–128 Ma) granites are of typical I-type derived from remelting of ancient crust of the southern margin of the NCC with input of mantle material under lithospheric thinning tectonic regime. The late-stage (127–112 Ma) granites include A-type and/or highly fractionated I-type granites, which commonly contain more fractions of mantle materials as exhibited by more depleted isotopic signatures, suggestive of an intracontinental extensional setting. Mo mineralization (155–130 Ma) related to the early-stage granitic magmatism includes mainly of porphyry or porphyry-skarn type with ore metals mainly derived from the mixed source of the mantle and crust, whereas the late-stage Mo mineralization (127–116 Ma) is mainly of porphyry type with the ore metals from similar sources with more input of mantle materials. Pb-Zn deposits (144–130 Ma) associated with the early-stage granitic magmatism are mainly of hydrothermal vein and skarn types, whereas those (125–117 Ma) related to the late-stage granites are of hydrothermal vein type. The Pb-Zn deposits are most likely distal products of the Mo deposits, together forming a metallogenic system. Au deposits are located in the Xiaoqinling and Xiong’ershan areas, and were formed during Middle Jurassic to Early Cretaceous (163–118 Ma) mostly from 132 to 120 Ma. The ores mainly occur in quartz veins and altered rocks and are hydrothermal magmatic in origin with Au derived from a mixed source of crust and mantle.